Storage tank



FIG. 1 is a perspective view of a storage tank;

FIG. 2 is a plan view of he storage tank;

FIG. 3 is a bottom view of the storage tank;

FIG. 4 is a front view of the storage tank;

FIG. 5 is a rear view of the storage tank;

FIG. 6 is a side view, from one side, of the storage tank; and,

FIG. 7 is a side view, from the other side, of he storage tank.

CLAIM The ornamental design for a storage tank, as shown and described.